By Lydia LeongThe various reactions to Amazon’s VPC announcement have been interesting to read. Earlier today, I summarized what VPC is and isn’t, but I realize, after reading the other reactions, that I should have been clearer on one thing: Amazon VPC is not a private cloud offering. It is a connectivity option for a public cloud. If you have concerns about sharing infrastructure, they’re not going to be solved here. If you have concerns about Amazon’s back-end security, this is one more item you’re going to have to trust them on — all their technology for preventing VM-to-VM and VM-to-public-Internet communication is proprietary. Almost every other public cloud compute provider already offers connectivity options beyond public Internet. Many other providers offer multiple types of Internet VPN (IPsec, SSL, PPTP, etc.), along with options to connect virtual servers in their clouds to colocated or dedicated equipment within the same data center, and options to connect those cloud servers to private, dedicated connectivity, such as an MPLS VPN connection or other private WAN access method (leased line, etc.).